Siemens siprotec 7SA522, Руководство пользователя

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Functions
6-207
7SA522 Manual
C53000-G1176-C119-2
Delay timers When the initiate conditions are fulfilled, the associated timers are started. The circuit
breaker pole(s) must open before the associated time has elapsed.
Different delay timers are provided for operation after common phase initiation and
phase segregated initiation. A third time stage can be used for two-stage breaker fail-
ure protection.
With single-stage breaker failure protection, the trip command is routed to the adjacent
circuit breakers should the local feeder breaker fail (refer to Figure 6-97 or 6-98). The
adjacent circuit breakers are all those which must trip in order to interrupt the fault cur-
rent, i.e. the breakers which feed the bus-bar or the bus-bar section to which the feed-
er under consideration is connected. The possible initiation conditions for the breaker
failure protection are those discussed above. Depending on the application of the
feeder protection, common phase or phase segregated initiation conditions may oc-
cur. Tripping by the breaker failure protection is always three-pole.
The simplest solution is to start the delay timer
7
(Figure 6-105). The phase-segre-
gated initiation signals are omitted if the feeder protection always trips three-pole or if
the circuit breaker is not capable of single pole tripping.
If different delay times are required after a single-pole trip and three-pole trip by the
feeder protection it is possible to use the timer stages
7SROH
and
7SROH
ac-
cording to Figure 6-106.
Figure 6-105 Single-stage breaker failure protection with common phase initiation
Figure 6-106 Single-stage breaker failure protection with different delay timers
With two-stage breaker failure protection, the trip command of the feeder protection is
usually repeated, after a first time stage, to the feeder circuit breaker, often via a sec-
ond trip coil or set of trip coils, if the breaker did not responded to the original trip com-
mand. A second time stage monitors the response to this repeated trip command and
trips the breakers of the relevant bus-bar section, if the fault has not yet been cleared
after this second time.
BF T2-TRIP(bus)
(Trip
bus-bar)
7
7
Start only L1
Start only L2
Start only L3
Start L123
> 1
FNo 1494
BF T1-TRIP L123
Start only L1
Start only L2
Start only L3
Start L123
> 1
7
7
73ROH
73ROH
> 1
(Trip
bus-bar)
FNo 1476